Yes, I cheated on my AH while we were married. I still try to minimize it to myself, that it was "just" an emotional affair, ummmm.... except for that one time when we kissed..... oh and then after AH and I were separated; well that doesn't count because, ummm, we were separated. Oh and my affair partner was married, but "that's his problem, not mine".
The back story is more complicated, and provides plenty more opportunities for me to minimize and deny that what I did was wrong. I did LOTS of step work on this with my sponsor in Alanon. I accept responsibility for my part in it; I made my amends; and it is part of my past....
It was something I needed to get through, to get where I am today. It's almost indescribable the emotions I was feeling during that time. It was like I had woken up from years of being asleep, or even dead. It helped me realize that I had to end my marriage; not to pursue a relationship with my affair partner - but because I was so strongly attracted to him that I knew my marriage was dead. Somehow, the affair gave me the courage and confidence to move forward. A silver lining so to speak.
But, that's where I start to justify, minimize, and deny.....